New Brunswick

New Brunswick's humble scientist and the breakthrough that changed aviation

Wallace Rupert Turnbull worked for years in his Rothesay workshop helping to advance aeronautics, but he didn't want fame. He was all about the science.

Rothesay's Wallace Rupert Turnbull patented his variable-pitch propeller 100 years ago

W. Rupert Turnbull was a shy and modest man who shunned the spotlight, but his contributions to early aeronautic research were substantial. (42287, New Brunswick Museum)

It's not really surprising that Wallace Rupert Turnbull isn't better known by Canadians.

The New Brunswick engineer was a shy, modest man who made little fanfare about his work.

In fact, the story goes that his wife Mary gave him a warning when he became interested in "flying machines" in the days before the Wright brothers got their airplane off the ground.

"Don't, for pity's sake, let anybody know what you're doing, or you'll be put down as a flying machine crank," she is purported to have told him.

Granted, his neighbours had to have known something was up in the Rothesay barn he converted into a workshop. The 91-metre-long railway line with a propeller-driven flat car in the yard was likely a bit of a giveaway.

Anderson's barn in Rothesay, where Turnbull set up his first workshop. (Wallace Rupert Turnbull fonds, Turnbull-6, New Brunswick Museum)

The son of a Scottish immigrant who built a fortune in the banking business in nearby Saint John, Turnbull studied engineering in New York, graduating in 1893.

He would go on to do post-graduate work at the University of Berlin, and it's quite likely that's when he became aware of the work of glider pioneer Otto Lilienthal. 

Huge crowds would turn out to see Lilienthal fly his gliders off a man-made hill in Berlin called Fliegeberg in the years before his death in 1896. 

Whether that was the inspiration for Turnbull's interest in aeronautics, 1902 saw him back in New Brunswick and ready to begin his own investigations into so-called "heavier-than-air" flight.

Interior of Turnbull's workshop, 1919, when his efforts to solve the problem of a variable-pitch propeller were in full swing. (Wallace Rupert Turnbull fonds, Turnbull-53, New Brunswick Museum)

For Erin Gregory, the curator at the Canada Air and Space Museum, this is where Turnbull begins to shine as a scientist.

He builds a wind tunnel in his Rothesay workshop to test the efficiency of various wing shapes, the first of its kind in Canada.

And Turnbull fills notebook after notebook with data comparing the lift and drag of each model wing he tests.

"He was a very, very, very meticulous individual," Gregory said in an interview. "So all of his experiments, they're very carefully recorded, the data is very carefully recorded.

"It takes a lot of patience to record that kind of data when you're doing airfoil research or, you know, certainly research on air screws, as they were called at the time, propellers."

Rearview of Turnbull's wind wagon on a track built near his Rothesay workshop, from October 1910. (Wallace Rupert Turnbull fonds, Turnbull-42, New Brunswick Museum)

Turnbull shared his research and took great interest in the work of other aviation pioneers. He was a member of the Royal Aeronautical Society.

He corresponded with Gustave Eiffel, the engineer behind the famous Paris landmark, who built his own wind tunnel at the base of his tower.

In 1906, he visited Alexander Graham Bell, who was trying to get his airplane aloft.

There, Turnbull met Lt. Thomas Selfridge, who was an early proponent of the military uses of aircraft.

Selfridge would later visit Turnbull's Rothesay workshop, and bring with him Wilbur Wright, brother of Orville, the team that was first to get a piloted airplane off the ground.

Turnbull also corresponded with Bell's American friend Samuel Langley, an aviation pioneer who headed up the Smithsonian Institution and whose name is on the oldest military air base in the U.S. 

"He was just, you know, I would say, like a true scientist and just really, really all about the work and recording it and then sharing it, sharing it around with others," Gregory said.

A 1923 frontal view of an assembled variable-pitch propeller model attached to an electric motor for testing. (Wallace Rupert Turnbull fonds, Turnbull-136, New Brunswick Museum)

By this time, Turnbull had turned his attention to propellers. He had been using his backyard railway to collect data on the efficiency of various propeller shapes, and published his findings in Scientific American.

Turnbull had reached the conclusion that the ability to change the propeller angle depending on whether an aircraft was taking off, climbing, flying at level speed, or landing would vastly improve the performance of the plane.

"This is kind of the magic of the variable-pitch propeller, that you can adjust it very much the way you would the gears on a car or a bike," Gregory said.

"So you kind of need a different pitch, a fine pitch, to take off and land," she explained. "But when you're in the air and at a cruising speed, you know, a coarser pitch or, you know, heavier pitch is better.

"So it's all about the … size of the bites that the propeller is taking out of the air. So that has an impact on how quickly the engine is turning and how much fuel you're using and all that sort of stuff."

Perfecting a propeller like this would allow aircraft to be made bigger, faster and to carry heavier loads.

Schematic wiring diagram for Turnbull Variable Pitch Propeller No. 2, c. 1925 (1995. New Brunswick Museum)

The problem Turnbull faced was how to adjust a spinning propeller blade in flight?

He began working on the idea in earnest around 1916 while working for the Sage Company in the First World War and continued the project upon returning home after the war. On Feb. 7, 1922, he took out a Canadian patent on his first variable-pitch propeller.

This version used hydraulics to adjust the blades, but flight tests in 1923 at the RCAF base at Camp Borden in Ontario showed that, while his propeller design was sound, the hydraulics were not up to the task.

So Turnbull went back to his workshop and began the task of figuring out how to use an electric motor to adjust the blades.

It took another four years, working with Canadian Vickers Ltd., to perfect the new design.

On June 6, 1927, a test pilot put his new propeller through its paces at Camp Borden and declared it a success.

The propeller at 'normal pitch.' The photo was taken at Camp Borden in the summer of 1927, after successful testing. (42284 New Brunswick Museum)

Turnbull took out a U.S. patent and went to work trying to find a buyer.

But he struggled at first, Gregory said, possibly because of his shy, humble personality.

Eventually, in 1929, he signed a licensing agreement with Curtiss-Wright, a company that would be a dominant player in the aeronautic industry throughout the 1930s and '40s, producing thousands of aircraft powered by Turnbull's creation.

Turnbull didn't rest on his laurels. He continued to hatch ideas from his Rothesay workshop, even proposing a tidal generator for the Petitcodiac River, an idea that was taken seriously enough that a company was formed to try to make it a reality.

The original Avro 504K with Turnbull's variable-pitch propeller that was successfully tested in June of 1927. It is part of the collection at the Canada Aviation and Space Museum. (Submitted Ingenium)

He lived a quiet life out of the spotlight until the 1940s. That's when he would receive an honorary degree from the University of New Brunswick, and Maclean's magazine visited his home to write a comprehensive article about him.

True to form, there isn't a single quote in the article from Turnbull himself.

Gregory said Turnbull's legacy is an important one, despite the fact he's still not well-known outside aeronautic circles.

"Lots of times your inventions and your work has to be really sexy for people to know about it," she said. "And you know, unfortunately, when you're making these small components of things, you don't necessarily get that kind of flash.

"Meanwhile, that small component is, you know, very significant and can be quite a game changer in terms of whatever technology you happen to be working on, in this case, aviation."